Trigger mechanism for snap switches



1955 P. H. WINTER TRIGGER MECHANISM FOR SNAP SWITCHES 2 Sheets-Sheet 1 Filed March 16, 1953 INVENTOR. PFS LH- INTER 4 ATTORNEYS Feb. 1, 1955 P. H. WINTER 2,701,287

TRIGGER MECHANISM FOR SNAP SWITCHES Filed March 16, 1953 2 Sheets-Sheet 2 FIG. 6.

- INVENTOR. PAUL H. WIN TER LQ/QM HTTOR Mmmmmmm "Mao Q United States Patent TRIGGER MECHANISM FOR SNAP SWITCHES Paul H. Winter, Syracuse, N. Y., assignor to Pass & Seymour, Inc., Syracuse, N. Y., a corporation of New York Application March 16, 1953, Serial No. 342,551

Claims. (Cl. 200-172) This invention relates to switch mechanism and more particularly to mechanism for operating and mounting switches of the spring biased type.

It is a general ob ect of the present invention to provide an improved mechanism for operating and mounting switches of the spring biased type.

More particularly it is an object of this invention to provide a novel and improved trigger type operating and mounting mechanism for quick acting switches of the self biased type.

It is an important object of the invention to provide novel trigger and trigger mounting means comprising sheet metal parts including straddling wings connected by a fulcrum pin to permit relative movement, a spring being housed between the parts and wings and bearing against the trigger finger piece and an abutment between the wings of the mounting means.

A further important object resides in the provision of combination of? position stop means and mechanism for locking the trigger in on position.

Other and further objects and features of the invention will be more apparent to those skilled in the art upon consideration of the accompanying drawings and following specification wherein is disclosed a single exemplary embodiment of the invention with the understanding that such changes may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawings:

Fig. 1 is a top plan view of a trigger type switch operator and switch mounting shown assembled with a typical switch;

Fig. 2 is a side elevation thereof, a portion of the trigger and trigger mounting frame being shown in longitudinal vertical section to illustrate the lever mounting arrangement, the switch being shown in the off position;

Fig 3 is a view similar to Fig. 2 but showing the parts moved to the switch on position;

Fig. 4 is a view similar to Fig. 3 but showing over travel of the trigger;

Fig. 5 is a vertical transverse section through the trigger and frame taken on broken line 5--5 of Fig. 2 showing the trigger lock in the unused position;

Fig. 6 is an enlarged transverse section through the trigger and frame taken on line 6-6 of Fig. 4 and showing the trigger lock in active position;

Fig. 7 is a fragmentary side elevation showing the trigger lock in active position; and

Fig. 8 is a perspective view of the trigger lever.

The mechanism of the present invention is primarily intended for but not necessarily restricted to use in the handle of a portable tool or like device whereby the current for operating the same is under the control of the operator grasping the handle, by the simple manipulation of the trigger.

Referring now to the drawings, the assembled mechanism is shown in combination with a relatively small switch 10, preferably actuated by means of a plunger 11 extending through the upper face thereof. The frame of the mechanism is connected to and supports the switch and is itself intended to be connected to the tool handle or similar part. For assembly with the switch there is provided a plate 12 of relatively heavy sheet metal stifiened by a longitudinal rib 13 and adapted to rest on a resilient gasket 14 on top of the switch housing 10. Integral straps 15 are turned down from the edges of "ice the sheet metal plate 12 and received in channels 16 in the side walls of the switch. The ends of these straps are deformed as shown at 17 after being positioned in order to flare them into engagement with shoulders at the junctions of the channels 16 with widened portions 18 thereof, whereby the switch is not only mounted securely against the plate 12 but the two parts of the switch housing, normally parted on the line 20 are secured together. The gasket 14 may be of some resilient material arranged closely to engage the walls of the plunger to exclude dirt and dust.

The plate 12 is perforated as at 21 for passage of the plunger 11, and, at the right, is merged into the principal frame member 22 comprising a narrow elongated plate bent up at an obtuse angle to plate 12 and having parallel edges from which depending wings 23 and 24 are bent down at right angles. The wing 23 is relatively long, extending almost to the plane of the bottom of the switch, and is perforated as at 24' to receive mounting screws or the like whereby the whole assembly is attached to the tool handle or other part.

The wing 24 is much shorter and extends down only sufficiently far to support the other parts of the mechanism now about to be described. The wing 23 has an aperture 25 punched therein and a portion of the metal from this is left attached to the right wall and bent at right angles to the plane of the wing to form lug 26 seen in Figs. 2, 3, 4 and 6 and having the reduced upper end 27 over which may be fitted the coils at one end of the open helical spring 28 passing through an opening in member 22. This lug and its portion 27 thus form an abutment for the trigger spring. The free end of the part 26 is received in a notch 29 properly positioned therefor in the opposite wing 24 and may be suitably attached here if desired to reinforce the whole structure.

The trigger proper is a sheet metal part of saddle-like form including the slightly longitudinally curved and relatively transversely flat finger engaging portion 30 having similar wings 31 and 32 turned downwardly from the edges thereof and parallel to each other. They are spaced to straddle loosely the wings in the frame part. Near the right end of the trigger wings and the same end of wings of the frame and close up beneath the plate 22 of the latter a pivot pin 33 passes through the two sets of wings to provide for relative movement between the trigger and the frame. A tongue 34 extends from the left end of one of the trigger wings and is bent at right angles thereto, as shown in Fig. 1, to reach over substantially to the opposite wing. A corresponding but larger tab 35 is bent over from the opposite wing toward the first one and spaced downwardly from the first tab. A third tab 36 is bent from one of the wings toward the other sufiiciently below tab 35 to provide a slot 37 transversely across what amounts to a closed end on the trigger remote from the pivot thereof. The lowermost of these tabs 36 is adapted to act as a stop to limit the movement of the free end of the trigger toward the frame. In order to provide for adequate trigger motion this tab 36 bottoms in a shallow notch 39 in the frame and wings. The extent of outward motion of the trigger under the action of its spring is limited by mechanism later to be described.

For operation of the switch plunger, which for the purpose of this explanation but in no limiting sense, closes the circuit when depressed, the trigger is equipped with an operating lever 40 seen in detail in Fig. 8, and formed of a sheet metal stamping of irregular form. It has the outer portion 41 slightly bent and extending generally in the direction of length of the trigger to overlie switch plunger 11 to depress the same when the trigger is pulled. This portion 41 widens from the narrow free end to a width slightly greater than the overall width of the trigger, as seen at 42 in Fig. 1. It is then narrowed as at 43 so as to just pass through the slot 37 between the tabs 35 and 36 at the front end of the trigger. Shoulders resulting from the narrowing limit movement of the lever into the trigger. Just inside of the tab 36 the lever is sharply bent up substantially at right angles to the portion passing through the slot, as seen at 44, to prevent movement of the lever out of the trigger. This bent up portion is then bent reversely at 45 to proarenas? vide a knuckle normally engaging the inner face of tab 34, as seen in Fig. 3, thus fixing the position of the inner end of the lever in respect to the trigger. The portion extending relatively horizontally from 45, as seen in Fig. 2, is bent downwardly to form tab 46, the knuckle above which engages the under face of the finger portion of the trigger. The tab 46 is narrowed to provide prong 47 with adjacent shoulders to cooperate with the opposite end of the helical spring 28 compressed between them and abutment 26 and serving to hold the lever in the position within the trigger shown in Fig. 2 and to urge the trigger toward the off position where the end of the lever 40 iust clears switch plunger 11.

Reference to Fig. 3 shows that counterclockwise movement of the trigger causes lever 40 to depress plunger 11 actuating the switch to the on position. The plunger reaches a limit of inward movement provided by its construction and then terminates movement of the lever. If, however, the operator continues to press the trigger over-travel of the latter is permitted While the free end of the lever stops moving so as not to damage the switch.

Fig. 4 illustrates such over-travel of the trigger, and it will be noted that the free end of the lever remains stationary because of its engagement with the now stopped plunger. Continued movement of the trigger moves the fulcrum of the lever downwardly, which in turn imparts accelerated downward movement to the inner end of the lever, further compressing the spring. which has already been compressed by the movement of the trigger. The spring is compressed at an accelerated rate because of the multiplying action of the lever. Final stoppage of the trig er is effected when tab 36 bottoms in notch 38. On release the reverse operation takes place.

The mechanism which limits trigger movement toward the off position is also used to lock the trigger into the on position and comprises a transversely disposed plunger having a shank 50 slidable in close fitting openings 51 and 52 in frame wings 24 and 23, respectively. as seen in Figs. 5 and 6. Under the action of a helical spring 53 surrounding the shank and bearing on the outer face of wing 24, the head 54 of the shank is maintained in the depression 55 of the frame wing 23 so as not to interfere with the trigger wing 31. The maior portion of spring 53 is housed within the sleeve 55 whose outer end is riveted to the far end of the plunger. as shown. A large aperture 56 in trigger wing 32 provides clearance for movement thereof but at 57 its edge engages against the spring to limit movement of the trigger toward the off position under the action of spring 28, as clearly seen in Fig. 2. The opposite tri ger wing 31 has an opening 57' therein of a size to freely pass the head 54 of the plunger when properly aligned for this purpose. Its center is spaced the same radial distance from the pivot 33 as the centers of openings 51 and 52 in the frame wings and disposed so that it aligns with the plunger head only when the trigger is moved to the limit of its stroke as determined by the notch 38. At this time the p unger 50 mav be extended to the dotted line position illustrated in Fig. 6, by ressure on its sleeved end. extending the head bevond the Wing 31. as seen in dotted lines in Fig. 6. If the trigger is now released the spring 28 returns it toward the off position until the edge of the openin 57 engages the shank of the pin 50 and prevents further return movement. Pressure on the plunger may now be released and it will be held in the solid line position of Fig. 6 by engagement of the under surface of head 54 with the outer face of wing 31. The swit h is now locked in the on position, as illustrated in Fig. 4. It mav be released by pressure on the trigger in the on direction. brin ing it to its final stop on the frame and centering the head 54 in the opening 57. The head will now be pulled through the openin by its spring 53 to the sition shown in Fig. 5 so that release of he tri ger will permit its spring 28 to return it to the otf position.

In some uses of tri ger switches there is no requirement for locking in the on position and in fact that arrangement may be undesirable. Where such con itions exist the locking mechanism iust described may be omitted and sim er means provided to limit trigger movement in the off direction. For this purpose the pin 50 may be cut off iust bevond the trigger wing 32 and there headed over to fix it in position. The head then cooperates with the wall 57 of wing opening 56 to limit trigger movement in the off direction.

The device just described provides a convenient mechanism for mounting the switch from the handle of the tool and provides the necessary operating mechanism for turning it on or off while providing for overtravel of the trigger without damage to the switch. Facilities are provided for locking the switch in the on position and for simply releasing it by mere pull on the trigger. The whole mechanism is an extremely simple assemblage of punchings and stampings and can be made ruggedly and economically.

I claim:

1. In a device of the type described having a cover plate and housing clamp unit adapted to be applied to a switch having a biased actuating plunger and an opening in said plate through which said plunger is adapted to pass, the combination of a longitudinal extension angled upwardly from said plate, wings dependent from the edges of said extension, one of said wings being additionally depended to provide mounting means for the unit and switch, a trigger element of U-shaped crosssection having wings straddling said extension and overlapping and pivoted to those of the longitudinal extension near the upper end of the latter, a switch operating lever extending from the trigger to and over said plunger, an expansion spring compressed between said trigger and an abutment between said extension wings and acting to return the trigger to its ofi position and means cooperating with said wings to limit movement of the trigger toward off position under the action of said spring.

2. In a device of the type described, in combination, a frame including a base plate, wings depending from the edges of said plate, a lug on one of said wings forming an abutment between them; a trigger includin a finger surface, wings depending from the edges of said surface and spaced to straddle the first mentioned wings, a pivot extending through both sets of wings near corresponding ends of each and adjacent said base plate and surface, the opposite end of the trigger having closure means between the wings, the lower edge of which en ages the frame to limit the trigger movement in the on direction, a spring acting between said abutment and trigger to urge the latter toward the off position, an arm projecting from said closure means with the outer end extending for mechanism operation and means extending through all of said wings and slidable to lock one set to the other in said on position, said last mentioned means in one position providing a stop to limit movement of the trigger in the off direction.

3. In a switch actuating tri ger mechanism, in combination. a frame. spaced wings depending from said frame, a saddle-like trigger having win s spaced to stradd e the frame wings, means pivoting the tri ger to the frame for relative movement thereover, means biasing the trigger toward an off position, a stop and lockin pin having sliding movement in close-fitting holes in said frame, a shallow head on one end of said pin to en age one frame wing. a helical spring on said pin compressed between the other frame wing and a button on the pin end opposite said head. an opening in the corres onding trigger wing sized to clear said sprin and pin for movement of the trig er to the on posi ion and havin a wa l to engage the pin-spring assemblv to fix the off" posi tion of the tri ger. and a hole in the tri er wing adiacent the pin head of a size to iust clear the latter and so located on the win as to receive the head and adiacent pin part when the trig er is at least in the fully on position and the button is pressed.

4. The trigger mechanism of claim 3 in which means is provided on said trigger having yielding movement relative thereto when overloaded, said means being adapted to actuate a switch having limited operating movement. said last mentioned hole in the tri er wing being positioned to pass the pin head only hen said trigger is over-travelled resulting from said yielding.

5. The trigger mechanism of claim 4 in which p sitive stop means are provided for said trig er to limit said over-travel and provide for alignment of the said hole and pin.

References Cited in the file of this patent UNITED STATES PATENTS 2,511,271 Kaminky June 13, 1950 

